Fuel
Economy Spreadsheet

The Fuel Economy
spreadsheet is designed for use with standard Microsoft Excel (for any
version of Windows), and
Pocket PC Excel. Pocket PC Excel is a subset of the standard Microsoft
Excel, and only the subset
features are used in this spreadsheet

A new
row needs to be created each time fuel is added to the tank, use copy
and paste on the last row (Pocket PC Excel does not support macros).
The intention is that you use it every time you refuel, and that you
will fill up at least once every few refuels. Keeping track of
your fuel consumption is a useful diagnostic for your car's health.

Enter
data only in the columns with light blue backgound in the heading.
Light yellow headings are optional data entry

Fuel
consumption figures are calculated on the main sheet. The Reports
worksheet shows some examples of additional queries that you can use
and/or adapt to your purposes.

Calculations in each row use the speedo
reading from the previous fill to work out km travelled.

The
first fill will not have a previous reading, so fuel consumption can
not be calculated for it. Enter the date, but you need not bother
entering amt spent, rate (cents/litre). Set filled to 1.

For the 2nd and later rows,
simply cut and paste the
previous row, then overwrite the data entry fields.

Some
values are averages of the last 5 entries, and will not be calculated
until there are sufficient previous rows (the number of entries
averaged over can be changed)

Data Entry
Fields:

date

each time you refuel, copy the whole of the last row,
paste in the next row, edit the date, amt, rate, speedo, filled and
remarks data

amt

cost in $ of fuel

rate

cost per litre of fuel, in cents

speedo

speedo (odometer) reading at time of fill

filled

set to 1 if tank completely filled (to consistent fill
point)

locn

code for petrol station, Woolies discount starts with W

all
city

1 if all driving done in city conditions (no highway)

% a/c

percentage of time air conditioner is on (estimate, round
to nearest 20%)

remarks

notes as to anything special about fill, eg. if long
country drive

$us/barrel

cost of oil in $US per barrel (optional: only needed if
you want to check if whether your bowser price is related to world oil
price)

Calculated
Fields:

l

litres of fuel in fill (check against docket to help
verify data entry !)

km

km travelled since last refuel

km
since full

km travelled since tank filled

l
since fill

litres of fuel added since tank filled

km/l

fuel consumption in kilometres per litre since last full
tank (easier when working how far you go per tank)

l/100km

fuel consumption in metric units of litres per 100 km
(since last full tank)

mpg

fuel consumption in imperial miles per gallon (since last
full tank)

$
since full

dollar cost of fuel purchased since last full tank

cent/km

cents per km for travel since last full tank

lt
litres

(long term) litres of fuel purchased since first record (
I usually hide this column)

lt
av.
l/100km

long term average fuel consumption in litres per 100 km,
over period since first record in spreadsheet

last
5
l/100km

short term average fuel consumption in litres per 100km,
over period of last 5refuels. Could
choose a lower range, but if occassionally don't fill tank, lower
refuel range not so good. You can change the number of records averaged
over (goto entriesAveraged )

last
5
mpg

short term average fuel consumption in imperial miles per
gallon (over last 5 refuels)

car

name of car, in case you have multiple worksheets for
different cars

min
fc

minimum fuel consumption (mpg) in spreadsheet, for
comparing current value with, if you think in l/100 km, edit the
formula !

max fc

maximum fuel consumption (mpg) in spreadsheet, for
comparing current value with

km/d

average km per day since last full tank

targ
km

target km at which next service is due

srvc
days

days until the next service, assuming average km per day
continues

srvc
on

date expected for next service, assuming average km per
day continues

empty
km

km expected that tank will be empty, assuming fuel
consumption average of last 5 refuels

fill
km

kmexpected that tank should
be filled, assuming a 10% of tank capacity reserve, and fuel
consumption average of last 5 refuels

days
petr

no of days before petrol should be filled

fill
day

date on which petrol should be filled

fbt
km/wk

km/wk need to do to meet the fbt km target

act
km/w

actual km/wk over last refuel

fbt
reqd

km odometer reading required to stay on fbt target

fbt
shortfall

difference fbt reqd minus current odometer reading

FBT
Entries (made yearly, or when adjustments required):

see also later explanation of FBT Table

fbt
km
adjust

any extra km to be added to fbt end to account for long
trips or long absence of weekly km (-ve value reduces fbt end), and/or
reductions due to end of lease or out-of-service periods

Configuration
Data (set it once at start of spreadsheet use):

fbt
annual km

number of km needed per fbt year (see also FBT Table)

fuel
tank capacity

litre capacity of fuel tank

fill
when tank is % empty

used tank capacity percentage at which you want to refill
(best if less than 90%, 100% is empty)

max
possible entries to average over

5 is default, but you might want to average over more or
less depending on your style of use. Should be at least 2. If you
choose a number larger than available entries, it is automatically
limited to available entries.

Configuration
Data (you won't need to update):

lower

lower threshold for finding average of fuel consumption
(filters out out-liers)

upper

upper threshold for finding average of fuel consumption
(filters out out-liers)

l/gallon

constant for converting litres to gallons

km/l
to mpg

constant for convering km/l to mpg

km/mile

constant for converting km to miles

entriesAveraged

number of entries to average, including last fill, in
recent consumption figures; usually 5 is a good number

Fill Types:

filltype

desc

0

not filled either this or previous
fill

1

caltex or ampol, includes non-city
driving

2

woolies bass hill, includes
non-city driving

(actually
the one identified in cell PetrolStn)

3

other woolies, inclues non-city
driving

4

not used

5

caltex or ampol, all city driving

6

woolies bass hill, all city driving

(actually
the
one identified in cell PetrolStn)

7

other woolies, all city driving

FBT Table:

Provides data needed to check
progress against km targets, for example, as needed for FBT
requirements.

Each row represents a start and end period. FBT km targets have to be
met at the 1st April each year,
and possibly at the end of lease period. Where a vehicle lease is
started on a day other than 1st April,
the km target is pro-rata adjusted for the days left in the year.
Similarly, if it ends, it is pro-rata adjusted.
Each row calculates the pro-rata target required for the end of FBT
year, or end of lease.

start
date

start date of lease, or 1st April of a given year
(whichever is later)

entry required

end
date

end date of lease, or 31st March of a given year.

entry
required

fbt
st km

odometer reading on first day of fbt year (not likely to be
exactly same as end km of previous period)

entry
required

total
days

days in FBT period

calculated

non
avail days

any non-available days (e.g. panel shop and other repairs
> 1 day)

entry required (if any)

net
days

total days less non-available days (this is use to get
pro-rata amount of km)

calculated

km
reqd

odometer target for last day of fbt year (pro-rata'd to
account for net days < 365 and fbt_annual_km)